


O₂

by merkase



Category: Shingeki no Kyojin | Attack on Titan
Genre: Biological Warfare, Child Death, M/M, Near Future, Nonbinary Hange Zoë, Slow Build, Slow Burn, Tags updated as story progresses, bad government, rage virus, recolonizing a broken Earth, viral outbreak
Language: English
Status: In-Progress
Published: 2016-03-25
Updated: 2016-07-09
Packaged: 2018-05-28 23:28:35
Rating: Explicit
Warnings: Graphic Depictions Of Violence
Chapters: 4
Words: 21,034
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6349978
Author URL: https://archiveofourown.org/users/merkase/pseuds/merkase
Summary: <blockquote class="userstuff">
              <p>Deep beneath the ruined surface of Earth, Sina's second colony is ending. Blindsided by a viral infection with no origin and no name, Shiganshina is forced to declare its lowest levels a quarantine zone. Unfortunately, the colony's only source of aid has come in the form of Commander Smith's Scouting Unit, which is trapped on the wrong side of their barricades.</p><p>*ON HIATUS*</p>
            </blockquote>





	1. Quarantine

Levi moved in the wrong direction--the only person, perhaps, who did not seem to understand when the time was right for following a crowd. In this case, the masses were correct, moving as one body from the lowest reaches of the colony upward, towards the promise of safety. There was a checkpoint ahead, they were told, and then they would be allowed to board a train. They were promised time and asked not to panic and they didn’t. The residents of Levels 2 and 3 moved anxiously where they were led, skittish as cattle in a drive, but ultimately under control. The recorded announcement was an urgent loop of sound,  _ not a drill, calmly, leave all personal belongings. _ Levi had to fight for every step he took. 

One of the soldiers stopped him at the wide stairwell with a heavy arm to the chest, barring his way and causing a minor hiccup in the flow of traffic bubbling up from Level 2. 

“The evacuation is moving to Level 4.” The man had to shout over a steady cacophony of human voices and stamping feet, his breath moist and disgusting on Levi’s ear when he had to lean in to make himself heard. 

“I see that.” The shorter man ducked nimbly under the arm in his path, slipping into the crush of hot bodies on the stairs before anyone else could attempt to stop him. He wasn’t the soldier’s problem, anyway. Their concern for Levi’s safety was superficial and fleeting. 

It was a wonder that no one had been trampled yet in all the commotion--at least no one that Levi had seen. He had to turn sideways against the railing just to make it down, gripping the lukewarm metal so tightly against the human current that his fingers ached in response. The evacuation was relatively tame, but it was cramped with subdued urgency and there was a near constant pressure against his back, forcing the rail into his stomach so unforgivably and so continuously that he would almost certainly bruise. There was no relief on the Level 2 landing, where he was obliged to crab-walk along the wall where he took a similar beating from the front as well, hands and elbows everywhere. He had to smack several away from his face or he’d have black eyes several times over. 

But the crowd thinned out just below. As soon as Levi stepped down onto the last flight of stairs towards Level 1, the heat and pressure eased and he felt less like a tiny blot of coal being rapidly transformed into the world’s ugliest diamond. He had no idea that breathing the cooler air of an unoccupied space could be such a novelty, or the freedom that came with not being battered and jarred. Already aching in several places, he turned the corner and found the stairwell abruptly and starkly empty. No one else was headed down this way, but he also wasn’t entirely alone. Another cluster of soldiers milled around the Level 1 landing where the doors had been rolled shut like they were trying to keep a sinking ship afloat. 

“What are you doing?” The man on watch did not have to shout. The roar was all above them, like being in a cavern beneath some gargantuan waterfall. Levi could make the soldier out perfectly fine without requiring that his ear be assaulted by stale breath and droplets of spittle. That, at least, was an improvement upon his previous experience with the military. Several others looked up, but they dismissed the wayward civilian without interest, their nervous minds on other tasks. 

“Are you evacuating Level 1?” It wasn’t an inquiry so much as a demand, because Levi knew the answer. He had been expecting it. What did the stinking bowels of their colony matter to anyone? At best, its loss would be viewed as a vague misfortune and at worst, there were some who preferred to see it gone. Suddenly, a couple of the soldiers seemed more involved, sensing the anger in Levi’s presentation and meeting it with unthreatened curiosity. Levi drifted forward, making it clear to them that he was not lost or confused. “I don’t see anyone leaving this way.” 

“Level 1 is under quarantine,” the spokesperson soldier answered immediately. His jacket said Barkett. “No one will be coming up.”

No, of course not. 

“You’re going to lock everyone down there?” Levi’s voice was hard with accusation, though he knew it was no more this man’s fault than it was his own. The soldier had his orders to follow, and he was only one guard on an endless number of stairwells all over the colony. There was no sense in wasting anger on such a person. Intellectually, Levi knew that, but his fingers curled into fists at his sides. He couldn’t help adding, “You aren’t even going to sort through them?” 

“Rejoin the evacuation. Now.”

“There’s a school down there.”

“There are more schools up here,” the man snapped. 

“Is everything alright?” It was a woman, obviously Barkett’s superior judging by the way his back snapped into a perfect line at the sound of her voice. She strode over to them from the preparations her handful of men were making--unloading cases of weapons by the looks of it. Levi’s attention lingered there, thinking it looked a lot like they were preparing to go to war. Their leader had the efficient and uncompromising look of someone who would not be easily intimidated. Her eyes were cool when they landed on Levi. “Rejoin the evacuation,” she repeated. Firmly.

“What orders were you given?” Levi did not lift his head to look up at her--did not acknowledge that she was over a head taller than he. His eyes were sharp enough to cut her down to his own height anyhow. “Did they tell you not to let people in, or only out?”

“No one comes back up,” the woman confirmed. Her rank was uncertain. “If you want to go and die, we haven’t been ordered to stop you, but you should know that they probably won’t open these doors again until nothing behind them is moving. It’s gotten ugly down there.”

“Level 1 has always been ugly,” Levi snorted. “Now there’s just a reason for you all to pay attention.”

The woman’s lips thinned, but she gestured for the heavy doors to open. They didn’t let the motors take them all the way, stopping them with only the barest foot of clearance between them, but it was enough for a small person to slip through. 

But the captain or lieutenant or whatever she was stopped Levi again before he could leave. “Who are you going after?” She wanted to know. “Who is that important to you?”

“Family.”

“Family,” she repeated, a quiet scoff her only judgment on his answer. “They’re dead or infected by now.” 

Levi did not wonder about her history with the concept of family--didn’t give a shit about whatever mommy or daddy issues she was harboring. He didn’t have time. “Maybe,” he acknowledged evenly, “but I won’t be the coward who left them.” 

“Wait.” 

Levi paused, half in and half out of the door, while the woman pulled one of the slim pistols from a holster at her thigh and offered it to him. It was illegal for a civilian to carry a firearm within the colony, but here was an authority figure holding one out to him, barrel to the floor and expression serious like she genuinely meant for him to take it. They really weren’t going to open those doors back up. “That’s the safety,” she said, pointing. “From there it’s straightforward.”

“Thank you.”

“Save the last bullet for yourself.”

 

*

 

The school wasn’t far or Levi would not have made it on his own. It stood, ground to ceiling in the open plaza where all of the central buildings were kept, looking grotty and untended even without the blood spattering its face. In all honesty, the school itself wasn’t all the worse for wear. Around it, a scene of chaos. They’d evidently used the plaza as a staging area after the hospital overflowed, spilling infected victims into the open air and all but ensuring transmission. Sheet-covered bodies lined the main thoroughfare like someone had gotten the idea to try repaving using the materials that were most readily available. And among them, the infected.

Some wandered, tripping over the dead and looking bewildered that they’d done so, their eyes glassed over with delirium. They bled. Their noses ran red, their mouths, their ears. Across the plaza, one of them hemorrhaged from the eyes in the advanced stages of her affliction, slinging infected blood as her thrashed. Another drifted close, drawn by the noise, and the woman absolutely lost it. She grabbed the newcomer by the ankle and dragged him to the filthy stone--a teenager who hadn’t yet outgrown his baby fat--and climbed over him, a high and unhinged wail issuing from her throat as she reached down and proceeded to tear the unprotesting boy apart. 

Levi could not look anywhere else. He felt all the heat of anger go out of him, giving way to the kind of full-body shock that spilled over a person like ice flow. It was the unnatural way that the boy lay there, allowing her to utterly destroy him like it was nothing to him, all without making any sound of protest or pain. He only seemed dazed, his eyes blinking slowly before the woman tore them from his face. She was using every weapon she had, her fingers, her teeth, her own forehead, which she slammed repeatedly into the side of the ruined face beneath her like a battering ram. Over and over, painlessly. She screamed, but it wasn’t agony. 

Others were converging upon her position, drawn from every part of the plaza like ants to a carcass. Some, like the boy, took their meandering time while others sprinted, hurtling wildly over bodies with a swift dexterity that seemed completely opposite from their staggering, uncoordinated counterparts. But all of them, one by one, fell upon the screaming woman. Infected or uninfected, if it was alive and moving, they seemed to go after it. The others came until she disappeared beneath them and the screaming stopped, her vocal cords disconnected from their housing.

Eventually, it occurred to Levi that he should move while they were occupied by their violence. The dog pile had become a frenzied mess as quicker victims tore relentlessly into their slower comrades. It was like they couldn’t differentiate at all between infected and uninfected. They weren’t simply annihilating. They were self-destructing when they were through--a self-eradicating plague. Levi pulled his shirt up over his nose and edged sideways along the wall, keeping the outer edge of the plaza to his back and the enormous support pillars to his front. Between the two, he was partially concealed, forcing his movements to remain slow and smooth despite the wild, desperate beating of his heart and the cry of adrenaline in his blood,  _ get out, get out. _ The gun in his hands was useless, but he held onto it like a lifeline. He didn’t know how many rounds he had, but he did know that there were more of the infected than he had bullets. He also knew that the second he fired that first shot, he would be dead. 

He went in through the teacher's entrance, which should have been locked and never was. The door did latch when it fully closed, but it never did make it that far. If left to fall shut without a helpful tug from the person leaving, the door did not build enough momentum in the swing to push the latch into its socket. Levi had taken advantage of this problem more than once, slipping in through the side to visit Farlan so he didn't have to wait around for one of those pointless visitor badges from the front desk. 

He pulled the door fully shut behind him, tensing when the latch clicked and freezing in place until he was certain that he was alone. The building was eerily silent around him, the way schools should never be. Even after all these years, Levi still thought there was something that felt apocalyptic about an empty school. Funny now that it was true. The man crouched to the ground just inside the break room doorway, listening hard for a long time before he carefully leaned out. 

Nothing. 

They had agreed to meet here a long time ago if anything ever went wrong and they were separated from each other. The school was in the plaza, easy to get to, and public. Levi and Isabel still dealt with the edgier side of life, where jobs were not always safe or easy for them and if things were to start sliding sideways there was nowhere less likely for them to be discovered than at a school, where they could hole up safely and wait for the storm to pass. Levi wondered if Farlan would still be there--if Isabel had remembered to come. If she hadn't, Farlan might have gone looking for her. Levi would never find them if that was the case. 

Something clanked, metal against metal, a couple hallways over. 

Not so alone, then. 

Levi moved as quickly as he dared, slowing only to edge carefully past each open doorway. Farlan's classroom was almost at the end of the long hallway, tucked up beside one other classroom and a door that led down a back way to the train terminal. That one had a much better lock on it, requiring a key card to move in  _ or  _ out. The technology was ancient, but it kept the children off the platform. If Farlan was here and he had his key card on him, that was the way they would want to leave. 

Naturally, the other man’s classroom door was barely ajar, blocking Levi’s view of the inside, where the rules of horror mandated that there would be an infected victim waiting to chew his face off. Levi tried peering around the obstruction, but he saw nothing in the small sliver of visible space on the other side. It was probably lurking behind the door. But this was Farlan's room. There were few other places for him to be. 

If he was here, the door would be closed. 

Levi reached out anyway, his fingertips pressing lightly into wood, where the barest flex of muscle had the door whispering open on its quiet hinges. He had never noticed before that they didn't squeak the way he'd have expected them to, but he appreciated it even if he needn’t have bothered. The classroom was empty. 

A tense search of the crevices--the space behind the desk, the supply closet--revealed nothing. There was no blood there, like the room had been successfully evacuated before things got bad, but where had they gone? Word was, no one on Level 1 made it out unless they were like Levi and coincidence had already placed them elsewhere when the outbreak struck. It had happened so quickly that at first, no one responded, rendered immobile by the shock of the speed and violence with which the pathogen spread. There was no way the students had been anywhere but in this building. The school did not come equipped with any sort of emergency shelter and why would it? Little could touch them so far underground and the one thing that could was not subject to the laws of a locked door.

Levi stood still in the approximate center of the classroom, turning a slow circle like he hoped that Farlan would appear magically before him. He was still thinking, trying to decide how likely it was that they'd gathered everyone in the auditorium or the gymnasium. Maybe they were still down there, barricaded in, alive. Maybe they were barricaded in, not alive. The halls certainly seemed clear like they weren't on this floor. The man was still standing there when the hallway came alive with sound--many sets footsteps falling out of sync and echoing harshly against the silence. They were light feet, small. Children. 

Jesus Christ, Levi did not want to kill an infected child. 

The door was too far away. He edged sideways, hoping to at least move himself out of their direct line of sight, but it was too late. In a wild, sudden tumble, four children came crashing in through the door, just piling in one after the next and freezing part-way through as their terrified eyes found Levi. He didn't think that fear was a facial expression that the infected made. 

“Mr. Levi!” One of them called. He recognized that face. He was one of Farlan’s students--the one with the weird name that Levi could never recall. “Are you--”

“Say something,” another of the boys demanded. The blonde. He looked like he might be one of Farlan's students, too, but Levi wasn't sure. 

“Are you being followed?”

The little girl breathed out in a gust of relief,  dragging the boy with the strange name the rest of the way into the room and turning the handle so the door would close behind them without clicking. 

“Will it lock?” The dark haired boy asked her quickly. They seemed to be in too big of a hurry to answer Levi’s question, but they didn't have to. Down the hall, something struck one of the small lockers, metal on metal. Again, metal on metal. Again. Again. Again. Advancing. The children backed away from the door. 

“Where is Farlan?” Levi asked them urgently. “You're his students?”

“He's down the hall,” the girl wailed. She'd been crying. They had all been crying, tear tracks still drying on their pallid cheeks. 

“He won't be for much longer!” The dark haired boy replied urgently. “Where do we go?”

They all looked at Levi. 

All the air had gone out of the man, his body frigid as the dread blindsided him. Farlan down the hall, but not for long. He'd rocked back on his heels. There was some other way they meant that. There had to be. “I …” Levi’s mind moved slowly, shock and disbelief rolling through him in crippling waves. Halfway up the hall, metal on metal, metal on metal, metal on metal. The moment passed. Levi had been silent for too long, his face slack. 

“The supply closet!” The blonde boy announced. 

That shook Levi out of himself. “No,” he rasped. It couldn't be Farlan. “It's too obvious. Can they open doors?”

“I've seen them try,” the girl answered for him, hesitating where she stood halfway to the closet herself.

Levi assessed the situation quickly. “Get in the cabinets.”

“Cabinets?” 

The children glanced over at them, doubtful. 

“There are books--” the girl began. 

Levi strode over and yanked one of the doors open. There  _ were _ books, stacked in several tidy rows from the back of the cabinet to the front, but there was space on top of them for a small body. A very small body. 

“Get in.”

Without waiting for her cooperation, he went to the next set of cabinets. It was the same situation, room for two in each section if they wedged themselves in atop the books and remained silent. Levi closed the doors on each. “Don't make a sound,” he warned them. “Stay still.”

They nodded as darkness closed around their terrified faces. Only the little girl stopped him.

“What about you?” she whispered. 

“What is your name?”

She frowned, confused. “Petra.”

“Don't make a sound, Petra,” was all Levi said. “Not for anything, any of you.” It was all he could say. They all might hear him dying outside, but he did not add that. Maybe they could weather it in silence. 

He almost went for the closet himself, but at the last moment, he stopped, turned on his heel. It  _ was _ too obvious. So was the space under a desk, but that was the only option that remained. If their pursuer looked in from the doorway, the room would seem empty. And if the closet was empty as well, then perhaps they would move on. Had the children been seen entering this room? If so, then by how many? He should have asked these things, but was too late and knowing wouldn’t change anything about their situation.

Levi pushed Farlan’s chair back and dropped to his knees to crawl into the small nook beneath the desk, reaching up and dragging the chair back in for good measure. From the front, it wouldn't look like there was much free space available under there. And there wasn't. Levi’s thigh rested precariously against the roller, so he had to keep a hand on it, pulling the chair into the edge of the desk and bracing it there so it wouldn't move. The sleeve of Farlan’s cheerful jacket swayed, wafting his scent into the air. It was subtle, but also unmistakably Farlan and Levi’s chest ached with homesickness. He’d attached his reckoning of home to this man and that woman--his family. That could not be Farlan in the hall.

The doorknob rattled once, then gave, admitting their pursuer without issuing any protest. The newcomer’s breathing was wet and labored like they suffered a terrible chest cold, but Levi knew better than to think it was something as benign as phlegm rattling around the dying person’s lungs. There was a bubbling cough, a disgusting splatter, and something hit the floor with a quiet slap. Levi was too busy worrying about controlling his breathing to be angry at this degenerate piece of shit for fouling up Farlan’s classroom with infected body fluids. He would be angry later if he could find the time. He knew that distantly even as he covered his nose again with his shirt and cupped a shaking hand over his nose and mouth to buffer the sound of his breath. 

First of all, Levi was fairly certain that there was only one of them. Secondly, they also had something that Levi needed. It sounded hard, solid, and if the infection had enticed its victim to grab it, then the item was probably a blunt weapon. Where had this person gotten a blunt weapon in a school? Levi’s mind listed things in desperation as the footsteps moved across the room in a leisurely exploration.  _ Crowbar? Chair leg? Wrench?  _ The storeroom closet door opened and it was like watching an anvil fall into the space he’d occupied just moments before. They could have been in there. Had the children been on their own, they would have been. 

Levi’s fingers tightened on the base of the chair, on his face where he grasped it, holding his ragged breaths on the inside where it was safe to keep them. His lungs burned with the need for more oxygen, trying to gasp, but that was the last thing Levi would allow. He took one slow, deep breath. Then another. The metal object in the infected person’s hands hit a chair leg and clanged harshly into the silence and Levi  _ wanted _ it. He wanted what that thing had. He wanted to lash out with whatever it was and keep lashing out until they were all safe.  _ Stay silent,  _ he begged the children.  _ Stay still. _

The infected didn’t even bother to search behind the desk. They didn’t come close, so it must have been a convincing scene that Levi staged. 

Ultimately, the footsteps receded. Levi could hear it when they hit the hallway because the end of that unknown weapon in their hands knocked lightly against the door frame as the body dragged past. Still, Levi waited for a few breathless moments before he moved, pushing the chair back carefully. He could hear their pursuer moving farther up the hall,  _ clink, clink,  _ and he had to catch up before they entered another classroom. Now was the only time Levi could be relatively certain what direction they. Away. 

The door had been left open. Levi speed-walked over to it, crouching again and easing his head out to look one way, then the other, like a child preparing to cross a pair of commuter tracks for the first time. The hall was clear on the open end and the man that had followed the children was headed even farther back, obviously interested in the last classroom on that side. His arms dangled at his sides, slack, clinging loosely to the item that Levi was after. It would be a simple matter to slip up behind him and take it before his grip could tighten, to plunge it into his throat or his face before he could react. Levi’s lips parted in delighted surprise when he saw what it was he carried. 

The fire axe. 

The school kept them in small, glass-fronted cubbyholes at intervals throughout the building. There was also a first aid kit and a fire retardant blanket in each one, and a portable defibrillator. Had the man broken into that emergency cache before or after he was infected? 

And then, the whole world ground to a screeching halt. 

That thin wrist was adorned. It was one of those stupid, woven friendship bracelets like the ones that all of them made together and exchanged. That had been years ago and Levi’s had looked terrible even when it was new, but Farlan wore it anyway. He’d always worn it. He wore it until it shrank, until the knot tightened to the point of molecular fusion. If the day ever came when he wanted it off, he would have to slice it from his wrist. The bracelet was dark with blood, but Levi recognized it--the bright silver thread he’d used for one third of the braid shining valiantly through the mess that frightened schoolchildren made when they were opened up and made to bleed.

Farlan.


	2. School's Out

Thirty feet, approximately. Levi’s eyes made the journey before his body moved, tracking up the hallway in pursuit of Farlan, who would undoubtedly turn and try to kill him as soon as he became aware of his presence. Levi would have to make it quick, hit him before he could react. Every muscle in the man’s body coiled like a spring, quivering with violent potential, but when he moved it wasn't to launch himself into the hall like an Olympic sprinter. He forced his feet to fall silently, closing far more slowly than he would like, but quickly enough. He would make it. 

The axe dangled so loosely from Farlan’s fingers that Levi wondered if he could feel how precarious the position was. The way that boy in the plaza had allowed himself to be destroyed without a single utterance of protest, without passing out from the pain, Levi couldn't imagine it possible that he knew anything about sensation. It had to be gone, all of it. 

How much of Farlan was gone? How much of him was left to kill?

But the teacher moved when Levi snatched the axe from his grasp. Some part of him was aware, starting to pivot, and the profile of that familiar, beloved face swung around with eyes so bright and alive that Levi hesitated, overcome with the idea that if he called out to him the other man would grin and throw his arm across his shoulders and tell him that f-bombs were not an acceptable part of middle school vocabulary. The blood sliding from his nose took a moment too long to register when those eyes seemed so remarkably untouched. 

Farlan did grin. There was blood between his teeth where it had sheeted from his nose and gathered. At least, Levi hoped that was where it had come from. He had a split second to consider the thought before the schoolteacher lunged. 

He was all over Levi before the little axe could rise, some strange, guttural sound warbling in his throat. He tried tearing into Levi as surely and violently as the woman in the plaza had torn into the infected teenager, his fingernails coming back and raking once, twice, into the shorter man’s shoulder, again into the side of his head. The larger man laid into Levi like his goal was to dig a hole straight through his body. Only, Levi was not the boy from the plaza. He felt pain and he struggled, his hand curling around Farlan’s neck to hold those infected teeth, that infected blood, away from his vulnerable face. The larger body strained against him, teeth bared with the obvious intention of taking pieces from Levi. He was heavier, had better leverage. 

Desperately, Levi swung. 

First, the axe hit jaw, shattering bone and causing Farlan's bite to shudder and lurch when he tried forcing the ruined mandible to open. The body barely flinched, his eyes giving nothing away. If Farlan felt anything over the pain or the makeshift brother he was trying to tear apart, it did not show there. It was gone, all of it. Heart pounding, injuries throbbing, Levi swung the axe again. That time, it hit home, blade sinking into the man’s brain case with a final, sickening crunch. At first, there was some resistance, then the bone gave and everything past that was soft and giving like the insides of an egg. 

Levi pushed the body away from him, staggering a few steps across the hall where his shoulder hit the locker and he bent, his back to Farlan, certain that he was going to be sick. There wasn't much in his stomach, which heaved, but gave nothing up, trying to empty contents that simply weren't there. A noise down the hallway stopped all of that activity before his stomach could try again, startled into polite quiescence by the threat of danger. His blind eyes rose, caught a wet blur of movement and he realized that he was seeing the world through his tears. 

“Petra?”

They were kids, but they weren't his kids. They weren't anybody's kids. They weren't kids at all, anymore. The axe swung. It swung until the hallway was silent again and his dominant shoulder throbbed in tandem with the injured one. He didn't know what else he’d acquired--wasn't sure if the infected children had scratched him, bitten him, gotten blood into him. He stepped across the scene of carnage he'd created and kneeled beside Farlan, who had thankfully, blessedly, landed face-down. 

The blood-smeared keycard was still clipped to one of the schoolteacher’s belt-loops, hidden just beneath the tail of Farlan’s stupid, business casual shirt where he had always kept it. Levi did not look down once he pulled it free, unable to face the friendly, familiar eyes that looked up at him from the ID photograph. 

Two of the children--his children, Farlan’s children--shrank back when they saw him. He must have looked bad if they'd mistaken him for one of the infected. “Come out,” he said to them. “The hallway is clear for now, but I made a lot of noise.”

“We know,” the dark-headed boy informed him. “It sounded like they were killing you.”

“I was killing them. Where is Isabel?” Farlan's kids would know Isabel. They would recognize her the same way they recognized him. They looked at each other. 

“They … were together. He …”

Levi didn't need the rest. He stood abruptly. “We’re leaving, then. Don't look at any of their faces.”

He looked cautiously around the door as they exited, but the hall was as quiet as he left it. 

“Woah, you killed all of them?” Asked the boy with the funny name. “All by yourself?”

But Petra smacked him. “Auruo, shut up. That's Mel.”

The boys took a few startled breaths. 

“I told you not to look at them.” Levi didn't turn to see if they were following, stepping over the minefield of bodies underfoot as he made his way past the infected corpses and towards the terminal door. He didn't count them, but he didn't need the numbers to know that it was a lot. The children trailed after him like horrified ducklings. 

“Is the metro still running?” Eld asked him, clearly intent on directing his attention elsewhere. “They haven't shut it down?”

“If they have, we’ll follow the tracks. Either way.”

“Do you have a key?”

Levi opened his hand to wordlessly show them his prize, swiping it along the ancient card reader and pushing the door open when it beeped. 

The emergency track lighting was on, which wasn't a good sign. The tiled tunnel sloped down, curving sharply as it spiraled and giving them no clue as to what the platform below would look like. Levi stopped them towards the bottom, the school door carefully closed and locked behind them. There wouldn't be any problem from that direction. 

But Petra reached out to grab his hand as he turned. “Wait. You're going by yourself?”

“Can you shoot a gun?” He asked. She shook her head, aghast. “Then I'm going by myself.”

“My dad is in the Guard,” Auruo volunteered, holding out a hand for Levi's extra weapon. “I've never shot a gun, but I've seen him take his apart. It looks easy.”

Levi eyed the boy doubtfully. He was so young, his voice unbroken, but all five of them would die if they couldn't defend themselves against the nightmare they found on the platform. Levi watched Auruo point the gun at the floor and take the safety off like he’d been handling a firearm all his life and maybe he had. Despite what he said about only watching, there were some down here on Level 1 who knew what they shouldn't know. Levi nodded. These were children, but he wasn't going to kill them because he tried to protect them from the violence that would save them.

“You stay right at the entrance of the tunnel and shoot only if something makes it past me. Your only concern is defending the three behind you.”

Pale, but agreeable, Auruo nodded. 

“Is that the only one?” Eld asked, stepping forward like he was volunteering for a suicide mission. 

“We’ll find something else on the platform once it's clear,” Levi assured him. “We can't rely on something as noisy as a firearm anyway.” He turned back to Auruo, who looked ready to follow him into Hell. “I’ve seen them drawn to sound. Only shoot if you can't do anything else.”

“Only if they make it past you,” Auruo agreed. 

Together, they stepped up to the last corner and Levi reached to place a cautionary hand on the boy’s shoulder, stopping him so they could look around before they dove in. Succinctly, Levi dropped that f-bomb that Farlan wasn't there to chide him over. 

They'd found where most of the teachers had gotten off to. 

Unfortunately, they hadn't quite reached that brutal, self destructive end-stage where they tore each other apart. They were still mobile, still seeking uninfected targets. They hadn't yet become so deranged that they began turning on each other, though they nipped. As Levi watched, one of the slower ones staggered lightly into another's shoulder and it lashed out automatically, hypersensitive to stimulation. But the two parted without any further bloodshed. 

“There's too many.”

“Too many at once,” Levi agreed. “Let me watch them for a second.” 

They didn't have time to wait them out. It could take another day for them to degenerate to the point where they started killing each other, and the sooner they made it back up to that door, the more likely it would be that his helpful guard unit would remember his charming disposition and let them through. Well. The children had a chance, anyway. They had a sort of scrappy cuteness to them that might warm enough hearts to make a difference.They would take one look at Levi himself, blood-slicked and injured, probably infected, definitely exposed, and refuse to let him pass. There was nothing in the world that Levi could offer them in exchange for his own survival.

That was another reason to move quickly. He hadn't dared touch his bloody shoulder, even just to lift his shirt away so he could look at it, but if he’d been infected, he would need to get the children to their destination before  _ he  _ became just as dangerous to them as the rest of Level 1. 

There wasn't much for it, then. “Stay here,” he reminded the boy again, skirting around him and moving quickly for the closest of the infected. The axe was in her before it even occurred to Auruo to protest, and Levi caught her as she fell, lowering her quickly to the ground and slipping around the side of the nearest tunnel support. His back to the pillar, Levi looked back over at Auruo, pointing to his own eyes, then over his shoulder towards the rest of the platform.  _ Watch,  _ he mouthed, hoping the boy understood what he meant because there wasn't any way to see whose attention he’d drawn. The boy nodded, his eyes wide, and held up two fingers, tapping his right shoulder to indicate which side they were coming up on. Levi angled that way, watching Auruo for any sign that he'd seen others move. The boy’s attention was everywhere, flitting over the invisible enemies that surrounded Levi. The man’s heart sank, knowing when Auruo's  gaze settled that he was watching another one and trying to decide if he should call it. He made a face, holding up a single finger and tapping his left side. Great. 

The shadows on Levi's right shifted, a small collection of footfalls indicating that the right side had arrived. He grabbed the first as he came around the corner, registering in an instant that it was Ms. Weldson, the elderly librarian. She had osteoporosis. Levi slung her easily to the ground and planted his foot on her delicate sternum and her feeble scrabbling did not even penetrate his pant leg. Next was Rufus Entwire, the fucking principal. The principal had fled his students and his staff--the ones that hadn't come with him, anyway. 

“Coward.”

Levi curled his fingers beneath the knot of Entwire’s ridiculous tie and drove the axe into the large man’s forehead, turning his own face away to avoid the splatter and catching him, too, as he sagged. Using the tie as a handhold, he let Rufus drop slowly to the ground, yanking the axe free and turning to finish the wiggling librarian. 

He'd been seen. 

There was a moment of brief, heart stopping eye contact with the young woman who taught math next door to Farlan, then she opened her mouth and issued a bloodcurdling scream. She herself was not much of a challenge, even with half of a splintered broom pole in her hands. Levi snatched the bloody end and used it to drag her right onto the blade of his axe. When he passed the tunnel leading up to the school, he tossed the weapon into Auruo’s waiting hands, knowing he would pass it back to one of the children behind him. Two of four, armed. Their odds could be worse. 

He tried to stay within sight of Auruo so the boy could watch his back, but he also had to keep the drawing crowd away from the children’s hiding place. He cut down two more as they came at him from around the corner, shoving the first into the second and dispatching that one while it was still overstimulated. The first was next. The control booth was his objective, but climbing in there was a good way to box himself in if he miscalculated. It would be locked from the inside, he knew, but the ticket window was open. It was one way in and it was small--a perfect bottleneck. The children would be cut off from his aid, but he couldn't help them anyway. He had half the platform closing on his position and going to help them would only lead the infected over to where they hid. 

Levi had a bit of a running start, placing his hands on the counter and rolling forward into the booth.

His landing was ugly and painful. Levi rolled right off the opposite end of the counter and landed hard on something, his back bending unnaturally over the obstruction. Judging by the clattering crash of metal and plastic, it was the cheap folding stool intended for the control booth’s occupant who, luckily, was not at home. Levi looked wildly for an attacker in the dim, reeling light, but he found nothing. Staggering to his feet, he kicked the stool viciously aside and stumbled to the controls, his eyes scanning over them quickly. There was no time--no time to fiddle with them and guess at their meanings. His open palm slammed down onto the first button that made sense--a small one in the top corner that was tucked away from the rest and protected by a plastic cover, which had been left open. The control panel brightened, the whole booth coming alive with light. 

There was a train coming. 

Levi laughed humorlessly, his relief short-lived. Bodies were slamming into the side of the booth, causing the rickety old structure to shudder along its frame. He moved quickly, planting his axe into the first, the second, knocking reaching hands away as he worked. He paused when he could to knock the side of the axe against the counter, the metal window frame, riling his attackers into a wild, thrashing frenzy. The commotion would draw them all here, to this window, where he would dispatch them one by one until the platform was as quiet as the hallway up--

A gunshot. 

Levi could see in their faces the moment he became the least interesting thing in the vicinity. The shot had been loud, resounding through the platform with damning strength. Outside the window, eyes rolled. Bodies spasmed, the ones closest to Levi trying to fight their way out from beneath the ones atop them. They grabbed onto their neighbors, pressing them down, trying to climb them if that meant getting to that noise. Everything was an obstacle. Levi slammed the axe down and some turned back. He was quick enough to slaughter these, but the ones behind them were already gone, too many of them closing on the children. 

Farlan's children. 

Levi kicked the metal stool away from him a second time, lunging for the control booth door. It would open for him from the inside, and it did. The door swung back, offering him a perfect view of the group that ran for Auruo. There weren't a large number of them left--enough to utterly destroy four schoolchildren, but not too many for Levi to take down on his own if he was careful. 

Levi was fast. He dodged the slowest at the back, twisting effortlessly around grasping fingers and sluggish bodies. By the time they turned to orient themselves in his direction, he was gone, closing in on the quickest at the head of the line. He sunk his axe into the first skull, taking it so quickly that it didn't even fight him. Another, he slung into its neighbor, sending both to the ground in a temporary reprieve. Auruo did not fire again, but Eld was there, driving the sharp end of the broom pole as hard as he could into the first of the fallen victims. It took him two tries. The second had rolled over and grabbed his slim ankle before Auruo joined him, slamming the handle of his gun into the side of the man’s temple. It did not slow the infected down very much, but it must have disoriented him a little because the interruption gave Eld just enough time to get the broom pole into it's head before it turned on his schoolmate. 

“Thanks!”

Eld didn't have a chance to answer. Levi had thrown another man to the ground and the boy was moving to overpower it before it regained its feet. 

“Go!” Levi called. “Towards the tracks!”

The slower ones were on them, forcing them to move, to keep ahead of them. When the children ran, most followed. Levi dispatched the few that remained, then looped around and fell in behind them, starting from the back and picking them off one by one, mopping up. 

He took one look at the quiet platform and slumped to his knees by Petra, utterly spent. 

“Mr. Levi!”

“I'm okay,” he got out. “Just out of breath.” He needed a minute, and they had one. They had earned it. “Look for weapons, but be cautious around the bodies.” He caught Petra’s hand as she started to go, releasing her quickly when he realized that he'd marred her pretty skin with infected blood. “Were any of you exposed?”

“I don't think so,” she said quietly. She reached out to touch the side of Levi's head, her eyebrows lifting with worry when he hissed, flinching away. “Just you.”

“I'll get you out. Go and find a weapon.”

Levi wasn't sure where the assemblage came from, but they returned with a large wrench, another fire axe, and a kitchen knife like the kind they used in the school cafeteria. Eld had exchanged his broom for a more durable rubber mallet. The gun was returned to Levi, safety on. 

“I'm sorry,” Auruo told him. “One of them had seen us and I knew Eld had the broom, but I didn't think.”

“No harm done.”

“I didn't realize,” Eld murmured. “It was harder than I thought to get the skull to break.”

“When you hit them, don't think they're going to stop,” Auruo told Petra and Gunther, who hadn't killed anything yet. “It's harder than it looks.” He sat heavily beside Levi and together, they all waited.

Far up the tunnel, a deep rumble announced the arrival of their ride, but it was still too soon for relief. Levi stood and ushered the children grimly from the striped edge. “Get around the side of the control booth,” he told them. “This one may be full.”

The train came quickly. By the time they heard it, it was practically on top of them, pushing a chilly funnel of air up the tunnel in front of it and sending Levi's hair flying around his face as it arrived. Full. 

Levi saw the bodies--too many, even for him--and moved to step back, but it was too late. The train had slammed to a stop and the doors rolled open, spilling them onto the platform in a dark, organized array of automatic weaponry and heavy boots. Their faces were clean. No blood. He was not immediately swarmed. Levi knew what he must have looked like, standing among the infected wearing their blood like he was one of them. Somebody raised a long, wicked rifle. 

“Stop!”

It was Petra, waving her arms. The other children followed, their clothing mostly clean, appearing ordinary and safe. Auruo and Eld had some spots, but for the most part they had to look alright to the men in black. 

The muzzle of the rifle rose. 

“If you shoot her,” Levi growled, “I will tear off your trigger finger and shove it so far up your ass that you won't see it again until I've reunited you in the afterlife.”

The shooter froze, glancing at her neighbor. “Captain?”

The captain in question was the size of an adolescent Grizzly bear and was about as furry, his beard and mustache rough and golden. The man shrugged. “They're speaking. They aren't vectors.”

“How the hell are you alive?” The young woman asked, her rifle dropping. “You look so much like one of them I almost shot you!”

“Are you infected?”

The man was clearly ranked highest, so Levi chose to answer his question first. His was easier, besides. “I might be. The children probably aren't.”

The man turned to look over his shoulder at someone else inside, still lost in the incredible crush of bodies. It was worse than rush hour on a Monday in there. “Commander!”

They had a captain and a commander? Goddamn, that was one crowded train car. 

And then, there he was. Reality shifted around Levi, the impossible colliding with the even more impossible to produce the ultimate impossibility that stood before him. He was as beautiful as a prince, all the baby fat smoothed away and refined into a strong jaw, powerful cheekbones. His eyes were the same perfect, cornflower blue. Levi would have known them anywhere even if he hadn't looked  _ exactly _ the same--all grown up but still, incredibly--

“Erwin?”


	3. R & D

**Notes for the Chapter:**

> This update took longer than I was expecting it to. I've been working on an original novel that's been taking a lot of my time, but I want to have this one done by the time Wild-Type is complete so I can focus all my fanfic efforts on the merman AU I have planned for afterwards. Updates for this one should come more quickly starting now. Should.

Levi saw his own expression as if through a mirror. Had he been everything in reverse--tall and bright, beautiful--he would have looked just the way Erwin did, standing there beyond the sliding doors with his lips parted in shock, his eyes blinking like there was a hallucination before them.

“Get them onto the train,” the commander said faintly.

His soldiers had not been expecting such a response. They turned their heads, perhaps at his tone if it wasn't the order itself they couldn't comprehend. Some looked to Erwin while others looked to see what Erwin found so important about the banged up little mongrel and his entourage of brand new orphans, but their confusion was uniform.

“All of them,” the commander had to prompt. “Now.”

Erwin stepped aside for the rapid procession that followed, allowing his captain and the dark-haired man to take Levi one by each elbow and haul him roughly into the train car. The children followed, though the soldiers were gentler with them by a slight margin. Still, when they took hold of Petra, Auruo actually raised his axe like he was perfectly willing to sever the offending hands. Levi saw it all reflected in the filthy glass and turned to bark, “Stop it.”

His tone even made Erwin’s soldiers pause--something that lifted the commander’s ample eyebrows a fraction. Auruo let his arm fall, expression sour.

“It looks like you have a squad of your own,” the captain laughed. He didn't bother concealing his curiosity. In fact, he looked as though he would welcome some reply. Levi didn't give him one. “I’m Mike.”

Levi looked him over without interest and did not return the introduction.

Erwin wasn't paying them the slightest bit of attention. Once his initial shock wore off, the man was all business, returning quickly and naturally to the duties required of him. “Wrap it up,” he was saying, waving black-clad personnel back into the train car. “We’re moving out. Were there any others with you?” The question was for Levi, asked briskly.

“This is it.”

Levi could see the mental tally Erwin made--one adult, four children, all minimally armed--and he could see the questions as they formed behind those eyes, only to be calmly set aside for later. “Hanji,” the commander called out. “Get these doors closed.”

Only then did Levi realize that his group was not the only set of civilian clothes in the vicinity. The conductor’s box had warped over time, its cheap plexiglass windows bending into funhouse mirror waves. Levi could see the figure inside--could see that they were colorfully clad, but little else. He hadn't the faintest idea what manner of creature a _Hanji_ would turn out to be, but they waved when Erwin called to them. Maybe the view out was better than in. Or maybe they couldn't see Levi at all and they were just acknowledging the order. Either way, the train shivered lightly as the doors squealed shut.

“Do you two know each other?” Mike asked, his eyes moving curiously between the pair like he hoped to see the answer hanging somewhere between them.  

“No, not at all. I thought he just looked like an Erwin.”

Nearby, a blonde woman squinted. “He really doesn't.”

“I did this thing in market plazas for a living. He’s an Erwin.”

He could tell by the look on the woman’s face that she couldn't read him at all. She was trying to decide if she thought Levi really had been any such thing, though she clearly leaned towards skepticism. Then Erwin spoke up and dispelled the ruse, the train lurching forward and giving him the time he needed to indulge his curiosity.

“Levi …” It was awkward in a way that nothing between them had ever been. “When did they assign you to a colony?”

“It's been a while.” His tone did not invite further questions. Erwin visibly struggled with the crate-full he had, his desire to thoroughly interrogate the other man warring with the uncomfortable awareness that the car was so silent a pin drop would be perfectly audible to every curious ear present. “So. I see your face never grew into your eyebrows.”

The silence around them became unbearably oppressive when the whole unit tensed as one body. This was something that had come up in barracks, surely. The commander’s eyebrows. Very commanding, ha ha. They’d obviously never mentioned them to Erwin directly.

The blonde snorted. “I see you never grew.”

One corner of Levi's mouth twitched upwards and the soldiers relaxed tentatively.

“I can't say I expected to find you here.”

“I’d say the same. You wanted to be a schoolteacher the last time I knew you.” The accusation in Levi’s tone came out a little strong, but it should have been an easy thing to understand. The Shiganshina soldiers were lax where they should be attentive and unyielding when they should stand down. They were often cruel and indolent. Perhaps there was more discipline where Erwin came from. Perhaps not. Levi eyeballed the man without turning his head, which would undoubtedly cause him to break his nose on Mike’s gargantuan arm the way they were all packed into that filthy train car like sardines in oil. Erwin didn’t look like the same sort of government-sanctioned thug that Levi was familiar with. He was stoic and professional.

But here he was, a soldier.

“I had to find another way to improve the world, it turns out,” was all he said for himself.

Levi snorted. “Well, then I hope your colony is doing better than this one.”

“It is right this moment.” And then, as if he couldn’t squash the question, “Levi, _how?”_

The shorter man shrugged and he remembered his shoulder. “The world is very small these days. With only two colonies there was a fifty-fifty chance I’d end up at this one.”

“That isn't what I meant. How did you get _here?_ Level 1 of Shiganshina is where Sina sends its reformed criminals.”

Levi knew that. He’d been living here long enough to pick up on the fact. “Looks like neither one of us got to follow our dreams.” Levi eyed Erwin blandly, unaccountably ashamed. This strange version of Erwin could not do this to him. He couldn't appear from nowhere and make him feel this way, like Levi had done something to disappoint him. He had no place. The shorter man hadn't been accountable to Erwin for anything apart from his studies and that had been a lifetime ago. He'd been a different person then. By the looks of things, they both had been. He refused to look away. “And I haven't been reformed. Commander.”

The look on Erwin’s face was a true pleasure to behold. He didn’t ask any more questions and the rest of the ride was stiff and uncomfortable.

 

*

 

 “Commander,” Hanji called out from the control booth. “We’re nearing our destination. Two more stations.”

“Don’t open the doors when we get there. We do this as planned, take our time and see if our arrival draws anything to us. If the numbers are too large to handle, we move on to the next station and backtrack. Nobody rushes. Hanji, slow the train.”

There were some nods, one or two verbal affirmatives, but most remained silent. From the control booth, Hanji must have applied the break because there was a brief lurch, a swift apology, and then the cacophony of wheels on track dimmed to a dull roar. They were still a very loud, very obvious intrusion into this brand new world where a moving train was something to get excitably homicidal over, but now, Levi supposed they would only draw a crowd from one mile off rather than two.

The station was deserted except for a few bodies that appeared to have maxed out their meagre life expectancy before dying violently together in a mad frenzy. Levi did not bother trying to parse the grim tangle. His eyes skipped right over it to the set of glass double doors they’d sealed shut when the quarantine took effect. They looked different, though, and Levi leaned closer to Mike to look a little more carefully at the bodies. Yes, those were guards. This was the platform the commuter train never stopped at. It wasn’t for civilians.

“Research and Development,” the woman on his other side supplied. “We’re here to borrow their lab equipment.”

“What for?”

“Oh, he deigns to speak to the rest of us,” Mike commented, his face wearing a wry grin.

“You don’t have lab equipment outside the quarantine zone?” Levi asked. “At your own colony, perhaps?”

“They keep this department on the lowest floor in case something happens and they need to quarantine the whole level,” Erwin answered, only faintly disapproving. “Something like this, for example.” Levi’s head snapped around so hard that his neck popped audibly.

“You’re telling me that Shiganshina had some quarantine failsafe bullshit in place and they let people live down here in the danger zone?”

“They stored people here, more like,” the dark-headed man muttered. His uniform called him Dawk and his tone immediately had Levi bristling. “People they didn’t want to look at.”

“In any case, there isn’t anything this well-equipped on the upper floors,” Erwin interjected quickly. “Doctor Hanji needs to get a closer look at this bug in case it makes it out of quarantine and a vaccine becomes necessary. We’re here for another reason as well.”

“I don’t suppose it’s the excellent meal replacement rations.”

Erwin ignored Levi as effortlessly as he had when they were children and the smaller boy tried to interrupt their tutoring sessions with off-topic commentary. “The fact that this outbreak was sudden and viral begs questioning. Where did it come from? The most reasonable answer seems to be right here in R&D. However, Shiganshina’s council has no knowledge of anything like this being in development.”

“And you’re just going to believe them?”

“Absolutely not,” Erwin answered drily. “They wouldn’t admit to conducting any illegal viral research. We’re looking for signs that the outbreak originated at this location.” He pointed to the corpses. “Evidence like that.”

“So what? They’ve been dying all over level one.”

“Some are in a more advanced state than others, are they not? I assume you haven’t seen many corpses yet.”

“I’ve made a few.”

“Some of the first vectors will have dispersed outwards from the initial exposure site, if it was in fact an exposure and not a fast-acting mutation of some kind. A high rate of advanced infection in this department means that we can probably assume the outbreak began here.”

“Why does any of that matter to me?” Levi wanted to know. “You don’t have to talk me into staying by appealing to my curiosity. I’ll stay until you throw me under the train so long as it looks like we're safer together.”

Mike snorted, but no one said anything. A few of the infected had been drawn to the train, but overall, the platform seemed remarkably deserted compared to the others they'd passed, which had made Levi's crowded school platform look scarcely occupied. They were easy to dispatch when all Erwin’s soldiers had to do was stand there and tap on the glass and work them into a frenzy of frustration that, considering their advanced state, they inevitably took out on each other. It was ugly and slow, but it saved them the bullets and didn't put anyone in harm’s way.

Levi looked for Farlan’s children as soon as they were all unpacked, but they were seeking him, too, and they all wound up gathered together in a close cluster while soldiers fanned defensively over the platform.

“I'll have to leave the doors open,” he could hear Hanji advising Erwin. “If I close them from the booth out here, I suspect the train would return to its automated route.”

The commander nodded. “Stay with Levi’s group at the center of the formation.” Hanji had a gun strapped to one bony hip, but Levi wasn't convinced it hadn't been given to the doctor that same day.

“They don't react to pain,” Hanji advised them, “but they have all the same vitals. A stab to the heart or a slash to the jugular will still kill them. They just don't respond the same way we do. You may not see how close they are to death until they go down. They can keep coming at you despite their bodies being badly damaged and that makes them even more dangerous.”

Yes, that part, Levi had seen. “Thank you, Doctor.”

“Sure,” they said. “We’ll see about getting you all a little more properly equipped when we get to the labs. You need better protection for your airways than just your shirt. Something for the eyes, too.”

Levi hadn't even bothered pulling his up. The children had--probably in response to the respirators they’d seen the soldiers pull over their faces--but Levi was likely to be infected anyway, so he didn't go to the trouble. “Will there be a way in this lab of yours to test someone for the virus?”

Hanji’s eyes drifted grimly to the bloody gouges along the side of Levi's shoulders and head. They were bleeding an awful lot, like they didn't want to clot, and Levi wasn't sure if that was because he'd been infected or if it was simply the nature of a head injury. “The virus is still too new for a blood test to detect it,” they said. “But I could take swabs from the affected area and see if there's a visual match. The virus itself has a fairly common appearance under an electron microscope, but the infected cells don’t. They spike out, like sea urchins. A visual inspection won't be as conclusive, but it's better than nothing.”

Petra's hand slid into Levi’s and he looked down to find her troubled eyes on him. All of the children wore similar expressions, but there was no way to protect them from any of this. If Levi turned violent, he would risk killing or infecting them before someone put him down and he wasn't willing to take that chance. If he had to, he would stay behind.

“Yes, please.”

Erwin’s voice drifted back to them from somewhere up ahead. “Alright,” he was saying. “Slow and steady.”

The group moved forward.

It was slow going. They moved as silently as a group that size could, passing closed doors and stopping just shy of the open ones. One person would take point on those, peering carefully around the corner before quietly moving to activate the sliding doors if anything was inside. The first time it happened that way, Levi stopped them.

“Those things can open doors,” he whispered up to Erwin.

“Not this kind. After quarantine protocols are initiated, they lock on closing and without an override badge they can't be opened up again. A standard employee badge won't do it.”

“Do we have an override?” Levi wanted to know. Erwin hesitated for a beat too long before replying.

“It's best that we all stay in the hallways if possible.”

“And hope that a lab with the equipment we need is still open,” Hanji added.

“After you do this are we leaving?”

The commander nodded. “Getting Hanji down here and back was our only mission. We’re headed straight back to the safe zone after we finish here.”

“And they'll let my group through with yours?”

“By that time, we’ll know one way or the other if you're infected. Barring any additional injuries, there shouldn't be an issue. This whole unit will go straight into quarantine anyway and they should have it set up by the time we arrive.”

“More quarantine,” Levi drawled. “Fantastic.”

“At least we’ll be the only ones to worry about up there. As far as we know, there have been no breaches from the lower levels. Shiganshina’s protocols are holding.”

Levi's snort was decidedly skeptical.

“Commander,” someone called softly from the front. “Is this the equipment we’re looking for?”

Hanji was gone immediately, turning sideways to slip through the tight crowd towards the lab in question. “Most of it,” their voice drifted back. “I can make this work.”

“We stop here, then. Nanaba, stick close to Hanji and assist if they need it. Mike, gather a small team and find us a vector.”

“A living one,” Hanji added quickly. “You can kill it before you try bringing it back--in fact, please do--but don't damage the brain because I want that.”

“That may be easier said, Doc,” Mike told them gruffly. “We’ll do our best.”

“Were the ones on the platform in an advanced enough state?”

Hanji nodded. “Probably, and it would be safer to backtrack rather than risk kicking some hornets nest up ahead.”

The blonde woman--Nanaba--slung an arm across the doctor’s shoulders and steered them safely off to one side. “Let us clear everything before you get too settled.”

“You four,” Erwin gestured to the first handful soldiers in the group. “Make sure the supply closets are clear. You four scout ahead and make sure we have a clear cushion of space around us. The rest of you, take the other side of the hallway and don't let anything past you.”

As soldiers moved around each other to obey, Erwin gestured for Levi and the children to follow him into the lab. “We’ll get you cleaned up once the room is clear.”

“What is that you're calling them?” Levi asked. “Vectors?”

“Modes of transmission,” Hanji answered. “A vector is a disease’s transportation. That's how they spread. In this case, the virus turns humans into vectors by compelling them to attack likely hosts. Vectors used to be a common thing, topside. Rabies, Lyme disease, West Nile, malaria, Chagas, _bubonic plague_ .” The doctor grinned and there was far too much actual excitement for Levi’s peace of mind. “It's a wonder anyone was ever free of disease up there. What _isn't_ a wonder is that the same evolutionary principle found its way down here.”

“I … see.”

“Do you?” Hanji asked. “It takes years for something like that to evolve naturally. It takes many, many generations. In that time, its visible. You see it coming. So why is it that we haven't _ever_ documented a vector-borne disease like this one down here? This isn’t something we got from our cats and the likelihood of something entirely new jumping species from insect to human in such an evolved state is incalculably minuscule.”

“So you think it was manufactured, yeah, that's why you're here. Got it.”

“Clear!”

“Clear!”

That was both ends of the lab. Levi was forgotten as the doctor bounded forward, thanking Erwin's soldiers as they went immediately for the supplies. “They normally keep clothing in labs like this as well. In case of spills or unanticipated all-nighters. You all need to get out of the bloody clothing. We don't know yet how readily the virus spreads.”

“Readily,” Levi guessed.

Hanji grunted distractedly. They'd taken a rolling instrument cart and dragged it over to the long workstation they obviously intended to use as a makeshift autopsy table. Their reverence for the items they transferred onto the cluttered station behind them was clear, placing them carefully despite the fact that no one would be returning to this laboratory for a long time, if ever. It wouldn't surprise Levi in the slightest if they sealed the whole level and started calling it _The Tombs_ as they raised a heartfelt monument to the people they’d left to tear each other apart.

“Well, you heard the doctor.” Levi moved to pull his shirt over his head, experimenting with the range of motion in his shoulder. He hadn't lost any mobility, but there was pain involved. Erwin's attention jumped immediately to the injury, following the thin trail of blood over his collarbone and down his chest.

“How recent is this?” Erwin asked him, and Levi understood why. It shouldn't still be bleeding freely after so long. Even if it had been brand new when they got on the train, it should have shown signs of clotting.

“I got it in the school. My shirt stuck to part of it, so I might have torn it back open.” He glanced pointedly at Petra, who was clinging to Levi's hand again with both of hers and looking positively stricken. Erwin’s eyes lingered on her upturned face.

“Don't touch it just yet. Let Hanji take a swab.”

“We need to get them cleaned up.” Levi was referring to the children. Mike and Nanaba were already standing with the boys by the sink, stripping them to the waist and dabbing carefully at their faces with some cloth they'd found in the upper cabinets. It appeared to be some sort of washing station they were using. There was a rack of inverted test tubes sitting on one side of the counter, another tub of liquid with more equipment inside. Levi hoped they had the sense not to touch any of it.

“We need to get _you_ cleaned up,” Erwin countered. “Nanaba can tend to Petra when she and Mike finish up with the boys.”

“I'll take her,” Hanji volunteered. They approached with a bundle of sheathed cotton swabs like the kind they used to test for flu. “Let me collect some samples, first.” They passed all but one of the tubes to Erwin to hold, their hands already safely gloved.

Levi held still and consented to being poked and prodded by the surprisingly ruthless little cotton tips. Hanji leaned in close, dabbing at each wound individually and passing the samples back to Erwin in exchange for fresh swabs. Levi supposed they were trying to avoid spreading the virus from one wound site to the others, but it couldn’t have mattered. If it was in his system it was in him whether the doctor spread everything around or not. When they finished with his shoulder, they had him turn his head to one side so they could sample the ones there, too.

“I’ll have a look at these once Petra is ready to go. Don’t try cleaning this mess yourself. If you haven’t been infected, but you have the bug on you, we don’t want it entering your system. Erwin, wear gloves.” Hanji peeled their own pair off and held their hand out for Petra to take, leading her away from the table they’d just cleared.

“So. You’re a paramedic now, too?” Levi reached back to push himself up onto the cold metal, putting his shoulder at Erwin’s eye level. The box of exam gloves that Hanji had left out were not his size, but the commander pulled them on anyway, wiggling his fingers carefully into holes that were too small.

“I do a little bit of everything,” the man replied. “Hold on, we need clean water.”

There was a whole cabinet of glassware over one of the sinks. Stepping around Hanji, who was crouched on the floor with their head under the counter, he reached up for a few. He moved differently than he used to, Levi noted. He carried himself differently. He’d been honed, crafted into something precise and disciplined and lethally capable. He’d lost that loose, easy confidence he’d once possessed. The confidence hadn’t gone anywhere, but he was keenly aware now of what his body was doing, how it balanced. There was an intent that hadn’t been there before.

That wasn’t everything that had changed. The boy he’d known had broadened out, filling in height with muscle until he was solid and well-proportioned. That change, at least, was favorable. It worked for him, even if it was ever so slightly unfamiliar. Levi wouldn’t mind getting used to that particular difference, he thought, watching a hard back solidify beneath that unflattering uniform shirt as Erwin bent to see what Hanji had found. He saw little point in looking away from the sight, so he didn’t.

“All we have here is alcohol,” the doctor was saying, passing a bottle up from beneath the cabinet. “It isn’t ideal, but it’s better than nothing.”

“Isn’t there a first aid kit?”

“There was supposed to be.” Hanji pointed to an empty bracket on the wall near an emergency eye wash station. “Someone took it. There’s gauze and tape, though.”

Erwin turned and paused, caught up short at finding himself under observation, but there was no guilt in Levi’s expression--nothing to give his thoughts away. “Well,” he said, holding up a bulk-sized package of gauze squares, “I don’t imagine we’ll run short.” He set the beakers down on one side of Levi and the gauze on the other, tearing open the thin plastic and pulling the first piece out. “What do you think they used these for?”

“Autopsies,” Hanji called from several workstations over, where they were dispensing Levi’s samples onto glass slides.

The two men looked at each other.

“Ah. At least it’s a fresh package.”

Levi caught a smile before it surfaced and held it ruthlessly against the inside of his mouth. He would not be charmed by this strange version of Erwin. He knew nothing about this Erwin except for the person he used to be, a long time ago when they’d both been far too young to truly know themselves. He’d have hooked his calf around the back of that Erwin and that Erwin would have leaned in, his full lips parting.

This Erwin might have called that part of his life a phase.

This Erwin was more serious than Levi had ever seen him. With his free hand, he nudged Levi’s chin to one side, his ungloved fingers smelling faintly of the powdery latex from the glove he’d pulled onto the other. Those fingers took him by the jaw, holding his head steady in case he flinched. “Close your eye,” he said, but he was too careful for that to really be necessary. He’d squeezed most of the water from the gauze and left only enough to lift the blood, cutting a line across Levi’s eyebrow where he hadn’t even realized it had dripped. He worked slowly, leaning in, but not in the way he might have. His eyes were intent, never once leaving the open wounds he was mopping up.

“Your attacker got you good. Have you seen it?”

“No.”

“I think they might have wanted your face as a souvenir.”

“He was family.”

Erwin’s attention never left the cuts, but his brow did tense. He knew that Levi didn’t have any living biological family--none that he would claim. “I’m sorry. You said you sustained these injuries at the school. Was he a teacher there?”

“Yeah.”

“And the children?”

“His. From his class, not his loins.”

“How long had you been together?”

“Almost since I got here,” Levi answered before he realized what Erwin was really asking. “Oh. No, Farlan was like a brother. And there was one other. Isabel.” He didn’t know why he bothered telling Erwin all of this--maybe to distract himself from the way his skin pulled, his gummy cuts stinging in protest.

Erwin nodded slowly. “Do you know if she’s alive?”

“She’s gone, too.”

“I’m sorry,” the commander said again. The pile of used gauze sitting by his thigh had grown since Levi looked at it last. “I know it’s bad timing, but I’m going to have to disinfect these before I bandage them.”

Levi glanced at the gallon jug of alcohol. “Is that the right kind?”

“Hanji gave it to me, so it won’t kill you. It will only feel like it.”

“Can’t hurt worse than getting them did.”

Still, it was fairly close. Rather than rub at them, Erwin did it all in one go, cupping his free hand around the back of Levi’s head and pressing an alcohol-soaked gauze square to the cuts with the other. First, all Levi could do was suck a hard breath in through his teeth. When he let it out, though, it came with several words that he hoped the kids would not be adding to their vocabulary, his hands jumping to Erwin’s wrist like he wanted to tear his hand free. The commander took it all in stride.

“It’s bleeding again. Hold on.” Erwin dabbed at the oozing cuts with the corner of a dry square. “Hold this up here so it doesn’t run into your eye.”

Levi reached up and did as he was told without really thinking about it.

“Do we have something to keep the gauze from sticking to his blood?” Erwin asked the room.

“Leave it for now,” Hanji called back. “I have petroleum jelly in my pocket, but we may find something better.” They were busy at the moment, though, bent over a microscope looking at blood scrapings.

“I guess we’re moving right along,” Erwin stated, reaching for the gauze to start fresh with Levi’s shoulder. “I’d offer you some of the alcohol, but that _might_ kill you.”

Levi snorted. He hadn’t been able to see what Erwin was doing before, forced more or less to stare straight ahead and guess how far along they were by feel. His shoulder, though, he could see and Erwin went about cleaning it as carefully and thoroughly as he’d cleaned the man’s head. First, he marked himself a radius he was going to deal with, leaving the rest either for later or for Levi. There was no danger from the blood farther down his chest. All of that was away from open injuries. But there was blood elsewhere and that _wasn’t_ his.

“I don’t see a lot of splatter on your injured side,” Erwin told him, going for more alcohol to clean the infected blood from Levi’s neck and shoulders. “Were you careful to avoid contact? This looks deliberate.” Erwin did have the most work to do on the uninjured half of Levi’s body where most of the infected blood had ended up. The alcohol was cold, but nothing stung. That was a good sign, probably.

“I tried to avoid their blood when I could, but it isn’t always practical to turn your body to one side in a fight.”

He could see that the other man understood. “It looks like you managed it often. Let’s hope it saved you.”

Erwin worked on him for a long time in silence. His attention was absolute, trusting his men with the watch if not with Levi’s injuries. It felt like a sort of delicate restoration, like Levi’s body was some priceless artifact that required great care to repair. He’d forgotten the effect Erwin had on him, had lost the memory to time and distance. He’d forgotten how it felt when Erwin was focused on him this way, how this man had always touched him like he was worth something.

“Have you wondered how your men are taking this?” Levi asked, and it sounded dangerously friendly to his own ears. “They’re seeing their commander do some pretty lowly grunt work, doctoring your level one swine like a common army medic.”

“They’ll assume I’m using it as an opportunity to interrogate you.”

“Are you?”

“No, I’m making sure that this is done right so you aren’t exposed twice. Why, does it feel like an interrogation?”

“No.” Levi was surprised to find it didn’t. “It would be a good opportunity for you, though.”

“I don’t need to interrogate you. I know you don’t mean this company any harm.”

“I might. Maybe I have so strong a grudge against the military that I’m planning to attack you all despite the obvious benefit of letting your men get me topside.”

“You and your squad of vicious schoolchildren?”

“Don’t underestimate my schoolchildren.”

Erwin’s lips twitched faintly, but only half his mind was focused on the conversation. The rest was on Levi’s shoulder, which was about ready for a round of alcohol. Levi knew it was ready before Erwin even reached for the bottle. Those cuts couldn’t have been cleaner.

“Get it over with, then.”

That time, he was ready for the sharp, antiseptic burn and he did little more than grit his teeth and ride it out. The alcohol had him bleeding again, but maybe that was a good thing. Maybe if there was anything sitting along the margins of the cuts, it would be flushed safely into Erwin’s waiting gauze pad. The man reached up to check his head, drawing Levi’s hand away and dabbing at the smears of blood that remained.

“The bleeding has stopped. I would think that bodes well.”

“Just in time, too.” Levi reached over for a dry gauze square and took over where Erwin left off on his shoulder, catching the thin, watery blood that threatened to foul up all the commander’s hard work. This clean, Levi could see that the marks were pink and inflamed, and he inspected them closely as Erwin went back to work on the rest of him. “They look raw.”

“Any injury like that would look inflamed. They’re so close together. We each have a basic NSAID in our field kits. You can take some of mine. Oh.”

“You have iodine, don’t you?”

“I’m sorry, I didn’t think of it. It’s for potentially contaminated water.”

“That’s alright. The alcohol did the job. Besides, I don’t fancy being yellow.”

“Why not? Jaundice would be a good look on you.”

Levi snorted softly. “And here I was worried I wouldn’t recognize you. But you haven’t changed all that much, have you?”

Erwin had been leaning around him, scrubbing blood from the back of Levi’s hairline, but the other man’s words made him straighten. “In some ways.” He fidgeted with the gauze in his hands--something he wasn’t prone to doing. “But in a lot of ways, I haven’t.” His eyes rose to Levi’s face. “You need to know that I didn’t abandon you. I put in the transfer request and my father signed it. I did ask, I swear it. And he vouched for you. We tried so many times they started recognizing me at the immigration office.”

Levi shrugged stiffly, using only his good shoulder. “I guess I couldn't behave myself long enough for it to finish processing. That isn't your fault.”

“I missed you.”

“Then you’re out of your right mind.”

“Dad and I both were. He talked about how adopting you would keep us all together. He had the paperwork, but he couldn’t track your uncle down for a signature, and then we were reassigned to the colony.” Erwin was shaking his head. “Did you ever think it didn’t matter to us?”

“Of course not,” Levi lied. He’d always been good at lying and Erwin had always been good at seeing those lies for what they were. That had not changed, either, and his serious eyes went soft with regret.

“I’m sorry.”

“I said it wasn’t your fault.”

Erwin was silent for a long moment, then he went back to cleaning Levi up, briefly leaning forward to check the smaller man’s back for anything he’d missed. Satisfied with his work, he returned to the front, where the last that remained was the harmless trail of drying blood that was cracking into flakes over his chest and abdomen. “I’m not leaving without you again. If you want to come home, you’re coming.”

The way he said it made Levi think that it was possible, too. It probably was. The commander would find come up with reason why they needed him--some excuse to take him. The Shiganshina officials wouldn’t want to argue with him long over a man that meant nothing to them. But even Erwin couldn’t outmaneuver a virus.

“Don’t tell me I can come home,” Levi said quietly. “I’m dead.”

“Not yet,” the commander disagreed, shaking his sleeve down so he could look at his watch. “Eleven fifteen. Twelve hours from now and we’ll know for sure. Less. You were exposed over an hour ago.”

But Levi shook his head. “You should know more than anyone how much can happen in twelve hours. I can do that.”

Erwin’s hand stilled over Levi’s abdomen where the line of blood had just barely touched the waistline of his pants. The alcohol was a bright, icy point where Erwin pressed it to his skin. “I know you can. Do you want to?”

Levi hesitated, his reply guarded when he gave it. “You’ve done such a good job so far.”

The commander smiled a little, his free hand moving to Levi’s opposite hip where it was probably easier to brace the smaller body against all the wiping he was doing. That could have been called necessary and efficient. The way his thumb slid just beneath the waistline of Levi’s pants to brush over the sharp point of his hip--that was something extra. He did not look up at Levi right away, clearing the last of the blood first.

“Erwin.” Levi waited for the man to set his last gauze square aside and raise his eyes. “If Hanji finds anything on those slides, would you take me somewhere away from the children and end it?” He shook his head. “Those people are still alive when they turn into vectors. I don’t want to feel myself sliding away like that. I don’t want the children to see it happen and I don’t want to risk infecting them.”

Erwin closed his eyes and left them that way, but he had no protests. “If Hanji finds anything, I’ll take care of you.”

“You might wait to see if he has a natural immunity first,” the doctor said dryly, appearing at Erwin’s side like they’d been summoned. “He could be a medical anomaly. You never know.”

“He’s positive?” Erwin’s voice came out a little sharp, his fingers tensing over Levi’s hip.

“Inconclusive,” the doctor sighed, peeling a second pair of gloves from their hands. “I didn’t see anything on any of the samples, which is better than a positive result, but there isn’t a definitive way to visually confirm a negative. That’s because I could have missed the urchin cells. Not every one will be affected right away. But this is the best we could hope for. It isn’t positive.”

Erwin’s shoulders relaxed. “Looks like we won’t be shooting you just yet.”

Levi was not so quick with his relief. “I appreciate you looking, doctor, but ultimately we don’t know any more now than we did before. What will the first symptoms be?”

“It will be a fever first,” Hanji told him, “accompanied by a severe headache. It will come on quickly, but you’ll know it when it happens. There won’t be any doubt. If you feel either of those two things, tell someone immediately because after that the violence can start within the hour. Minutes, maybe, by now.” Hanji looked between them, their eyes serious. “The virus is evolving. It’s all accelerating rapidly as it becomes more a more efficient killer, so twelve hours is now an upper limit. It’s our absolute maximum time frame, but otherwise it’s become meaningless as a gauge. If you feel feverish or develop a headache at _any_ time, that will be it. You were infected by one of the more recent vectors.”

“I’ve had a caffeine headache for hours,” Levi muttered. “It will be a race to see which kills me first, the virus or the withdrawals.” Movement outside the front windows drew his attention to the handful of soldiers who were returning with a limp body slung between them. It was time to vacate Hanji’s table. When he slid to the floor, though, he found himself almost chest to chest with Erwin--something he’d half expected to happen, though it hadn’t been intentional. Not entirely.

Still, Hanji’s eyes moved between them speculatively. “If you guys are going to kiss, I would give it a few more hours. Just saying.”

Erwin glanced down at Levi and took a quick half-step back, putting a respectable distance between them. Maybe he would keep that distance. Or maybe, Levi mused, he wouldn’t.


	4. Bad Science

**Summary for the Chapter:**

> Erwin's unit meets the mad doctor.

**Notes for the Chapter:**

> If you replied to the publishing notes on the last chapter of Wild-Type, I haven't been able to open apps on my phone including the internet browser, so I haven't been able to respond to anyone. I'm going to start catching up later tonight on my computer after my grandfather's birthday party thing!

Hanji was swift and efficient with the body they’d been brought. They motioned for the soldiers to turn the vector over onto its stomach as they readied their hands for contact, already barking rapid-fire orders that the two men jumped to obey, their expressions vaguely frightened. It was clear they had expected to be finished with cadaver duty--had not anticipated being roped into the additional task of serving as the doctor’s grisly sidekicks. But no one came to rescue them, unwilling to risk being volunteered to take their places. 

“Both of you get yourselves into protective gear,” Hanji ordered, shrugging into a crisp lab coat. “Gloves, masks, and full facial shields are a must. If you don't want blood on your uniforms get lab coats. Everyone else stay away from the table. Now,” they turned to the men, their expression hard with businesslike severity, “which of you has the stronger stomach?”

Nile and Dita looked at each other. 

“Mike, Nanaba,” Erwin called, moving away from the table without regret. “Help us outfit the children.”

There were goggles and face shields in one of the cabinets over the sink, surgical masks in a drawer below. Erwin took a sizable handful and tucked them into one of his pockets in case the ones they put on the children were soiled somewhere along the way. When he handed the same equipment to Levi, however, the man was slow to move, his lips twisting into a wry smile. 

“Do you think it will matter?”

Erwin did not smile back. “There's no sense in risking you farther. You may not be infected.”

“Yeah.” Levi wondered what the odds of that were, but he took the goggles and the mask and the lab coat that Mike tossed him, looping the mask around his neck and setting the goggles on top of his head. Across the room, Hanji was just pulling a full shield over their face, some sort of electrical saw in their hand. 

“I'm going to have to cut into the spine and skull,” they announced. “There will be some noise.”

“We’ve cleared a perimeter,” Erwin answered. “Make it quick, though. We don't know how sound carries through the vents.”

“Would they be able to find us that way?” Levi asked. “Are they that clever?”

“I wouldn't rule it out,” Hanji answered grimly. “Alright, Dok, get that first specimen container ready. I'm not extracting anything from the spine yet. I'm just taking the vertebrae for now. Ready?”

The man nodded, looking faintly nauseous. 

Hanji turned on the saw. 

They'd already opened up the back with a scalpel, but there was still blood, and sections of the spine did not pop free once they were sawed apart. Hanji seemed to anticipate that, unconcerned by the resistance. They moved deftly with the scalpel, carving through flesh, fat, and sinew to twist each vertebra free with a sickening pop. 

“Are you taking the whole thing?” Erwin asked, and Levi could understand his trepidation. As efficient as Hanji was, it was still taking time. The doctor barely glanced up, unperturbed, though Levi supposed that anyone who could saw through a human spine with so little emotional distress wouldn't be perturbed by much. 

“Not the whole thing. Just several segments from the top and middle.” The saw came back on. Levi watched in fascination as Hanji tucked their chin to avoid a fine spatter of blood that had their assistants stepping hastily back. 

“How many times have you done this before?” Levi called over the high pitched scream of the saw. Hanji didn't answer until they’d turned it off and set it down to extract the vertebra. “A fair few,” they answered honestly. “I haven't kept count. I’m a microbiologist with a specialty in infectious disease, so we do a lot of autopsies. What are you two doing all the way back there?”

Nile stepped forward like he would rather be anyplace else, offering the container for Hanji’s most recently acquired vertebra. He winced when its weight was added and he was pointedly avoiding looking down. “Sorry. There was a lot of--”

“No need to be skittish. That's what the face shield is for.” But Hanji flipped the switch on the saw and Nile was stepping back again as the blood flew. Levi’s attention was mostly on that particular spectacle, so he missed the start of the next. Nothing seemed off to him until Erwin raised his voice over all the noise, calling for Hanji to stop. 

The commotion in the hall was explanation enough. Hanji looked up, so shocked that they didn't think to put the saw down. It just hung there in their gloved hands dripping blood over the cadaver as the shouting outside drew closer. 

“Erwin, the perimeter!”

“Stay in here.” The commander's reply was for Hanji, but it had been directed at all of them. Levi drifted closer to the table, looking around for the makeshift weapons the soldiers had confiscated from the children and coming up short. He mentally tallied their arsenal--Hanji’s handgun, a rifle and sidearm for each of the four soldiers present, perhaps a backup on an ankle holster and extra magazines. Mike and Nanaba had drawn, but they stayed where they'd been ordered to stay--between the door and the children. 

Someone was calling for Erwin out in the hall, waving at them through the thick sheets of glass along the front of the lab. 

“What's going on?” Levi could hear the man ask, stepping around the corner and coming into view again, his eyes already scowling over the man’s shoulder at something down the hall. He didn't look terribly alarmed, which was a positive sign. “Let them through.”

Levi saw them then--a man in a lab coat with a small child in his arms. The boy was smaller even than Farlan’s kids, barely old enough to stand on his own much less walk with any kind of haste. Erwin's men had been trying to extract him from the man’s arms, which had likely been the source of the commotion if the thunderous expression on the man’s face was anything to go by. He shrugged out from under the hands on his shoulders. 

“Are you responsible for these men?” he could be heard asking Erwin, his voice dripping with contempt at the indignity of referring to them as men. “Is this your operation?”

“It is. I'm their commander.”

“Then you had better command them to get their guns ready. I was followed.”

Erwin looked over the man’s shoulder, down the empty hallway he'd come from. Levi could see part of it from the angle where he stood, and Hanji was leaning into the glass behind him, trying to do the same. 

“Do you see anything?” Levi asked the doctor quietly. A minute shake was all he got. 

“How far ahead are you?” Erwin was asking the scientist. His skepticism was plain. 

“Not far enough.”

Erwin motioned for his men to draw their weapons, unwilling to take the chance that their new arrival was telling him the truth. He held up a hand for silence, and no one moved. They became so still that the rustle of Levi's clothing was clearly audible as he edged slowly into the doorway and leaned out. They all had to hear him, but none glanced over. Their weapons were trained on the far end of the hallway, fingers ready on their trigger guards. In the silence, it was clearly audible when it began several corridors back--the commotion of a large, noisy crowd approaching. Erwin's eyes jumped sharply to the scientist. “How many?”

The man shook his head. “Two dozen, maybe three. I closed the fire doors between us but those aren't connected to the quarantine system. They will open again if prompted.”

Erwin scanned the man's face like he didn't entirely trust it, though there wasn't much reason not to, considering their circumstances. Levi could see him come to that conclusion as well, because he turned to the side to let them through. “Both of you get into the lab. Stay away from the table.”

The scientist’s attention went immediately to the table in question, taking in Hanji's presence there and the cadaver they leaned over. Understanding crept into his expression. “Of course. I had wondered what your purpose was in coming down here. You have a scientist of your own.”

“How much longer do you need?” Erwin asked Hanji, taking the man’s comments as rhetorical. 

“I still need the brain. And a few more pieces of spine. Ness, get me enough preservative fluid to fill the largest container in my bag.”

The soldier looked around the lab, his expression baffled. “I don't know what that would look like.”

“Please, allow me.” The other scientist held the child out to Erwin, but the commander shook his head. 

“Levi will take him. I need to command my unit.”

“My name is Grisha Jaeger and this virus is mine,” the man said briskly. “You will want to have a conversation with me about that, I'm sure.”

Erwin took the boy that time without protest, shocked into compliance even as Grisha moved away from him to fetch the preservative fluid for Hanji. 

“You had the right idea about where to find the source of the virus.” True to his word, the man moved through the lab like he knew it well, going straight to the supply closet. He didn't speak again until he had emerged with the preservative. “I can't take full credit, as I'm sure you've guessed.”

“It bore more than a passing resemblance to the rabies virus,” Hanji answered sharply. “With some significant alterations.”

“I played with it a little,” Grisha admitted. “I fashioned it into what I needed it to be.”

“What could you possibly need to destroy a whole colony for?” Nanaba growled, starting forward only to be abruptly halted by Mike's hands on her shoulders. 

“My motives are not significant now. Not to any of you, who have so many other things to consider.”

“You failed,” Mike told him, his fingers visibly tightening around Nanaba. “The colony’s quarantine protocols have taken effect. You've only managed to destroy one floor.”

“Are you so sure?” The man asked. “You asked about my motives, not about my methods. This lab was only one of three origin points around Level 1. The original vectors are asymptomatic carriers. Children. They will be amongst the first in line at the evacuation points. From there, they could go anywhere, couldn't they? Sina, perhaps. Or your own colony.”

Erwin glanced down in alarm at the child dozing on his shoulder, pulling him abruptly away from his body. The boy whined pitifully, but didn't seem inclined to bite. 

“That is my son you're holding. Eren. He is not an original vector, but he is something just as extraordinary. He’s humanity's only chance of survival.” Dr. Jaeger reached out and, before any of them realized where it was he’d drifted over to, his hand was on the control panel and the door was sliding shut. Mike and Nanaba were closest. They lunged at about the same time, managing not to get tangled up in the suddenness of the action, and the doctor stepped calmly away to allow them access, understanding the futility of the gesture. Nanaba’s hands made it to the control panel first, but touching it did not stop the door. It touched the ground only seconds after her fingers made contact, and in the silence that followed they could all hear the dull grind of the lock sliding into place. 

“What have you done?!” the blonde cried, and Mike didn’t stop her that time as she closed on the doctor, getting her fingers around his thin neck and slamming him into the plate glass window with more strength than her smaller body seemed to have in it. “What have you fucking done?!” 

Dr. Jaeger couldn’t reply. Only a small choking sound came out of him as his knees sagged, his face going rosy with blood. 

“Nanaba, we need the rest of the story,” Erwin spoke up, glancing at little Eren Jaeger as he, too, started screaming, high and wailing. He was too young to know what they said, but his eyes were fixed on his father like he understood his distress. “Nanaba!” 

Levi stepped up and touched the commander’s elbow. “Give him to me. I may already be infected, anyway.” 

Erwin opened his mouth to reply--maybe to protest--but the child was squirming in his hands and he couldn’t do much of anything about the situation with Eren in tow. “Mike!” he called. “Get her off him.” And there wasn’t much he could do except pass the screaming child over to Levi, who turned him quickly away from the scene and tried doing that bouncing thing he’d seen parents do. It seemed to work on other kids and after a few moments it started working on this one, too. Miraculously. Holding him properly seemed to help, too, and he settled right down into sleepy cooing as soon as his head returned to somebody’s shoulder.  

Outside the window, the gunfire started. Hanji stepped away from the table then, looking out with Nile and Dita, who both crowded in behind them to see what was going on. 

“They have it under control,” Hanji announced, and the quality of the gunfire reflected that assessment. It wasn’t wild, panicked firing, but slow, occasional bursts. Most likely, they were taking vectors out as they pushed through the fire door at the far end of the hall. A couple at a time, they would be fine. 

“Stay at the back of the lab,” Levi told Farlan’s children, anyway. “Sit against the cabinets and keep your heads low.” 

“The glass is bulletproof,” Jaeger told them, his voice raspy. “We’re relatively safe in here.” 

“Why lock us in before we’ve even made contact?” Erwin wanted to know. “What haven’t you told us?”

The doctor looked up at them from the floor beneath the window, his expression languid with relief. “There’s nothing. It’s purely a precaution,” he assured them. “None of us can afford the loss of my son. If your men out there are overrun, we have a chance in here.” 

“Until they break in,” Nanaba spat. “Good fucking job, cornering us all.”

“Commander,” one of the men radioed in from the hall. “What’s going on?” 

“The doctor has taken it upon himself to lock us in the lab,” Erwin answered. “We’ll blow the glass as soon as there is a lull in the fighting and then we’ll all work our way back to the platform.” 

“Roger that, Sir. Are you all okay in there?”

“Everything is under control here. Stay focused.”

“Yes, Sir.”

Erwin turned to Jaeger, his expression stony. “Why do you imagine that your son matters more than the lives of my soldiers?”

“He has the antibodies you need to create a vaccine. Look, your own scientist understands.” He nodded to Hanji, who had looked up sharply to stare at Eren. “How long does it take to make a vaccine from scratch? To develop the antibodies? At the rate this virus moves, you’re going to want to skip a few steps. Eren is the only one. I synthesized one dose of a vaccine and administered it to him myself before all this began. He carries the cure in his blood.”

Erwin looked over at Hanji, who shook their head minutely before answering. “We can’t be sure he’s telling the truth, but can we risk that?”

“Why haven’t you gotten Eren out yourself?” the commander asked Grisha suspiciously. “Surely you had the time with all the advance warning you had.”

“I was unexpectedly delayed.” Jaeger reached over and pulled his sleeve up, rolling the cuff over his forearm where dark lines of infection spread from a ragged slice on his forearm. Erwin did not look surprised to see it. “I was nicked in all the fighting. Their blood must have gotten into it.”

“Serves you right,” Nanaba hissed.

Jaeger looked at her blandly, pulling his sleeve back down. “I imagine it does.” 

“How can we be sure he isn’t saying all of this to save his son?” Erwin asked Hanji. “Is there a way for us to test Eren’s immunity?”

“Not quickly.”

“Look at his left side,” the doctor instructed. “That should be proof enough.”

Levi glanced down at the boy in his arms, feeling everyone's eyes on him even before he looked to confirm it. Easing up the sleeping child’s shirt exposed a bandage on the lower part of his rib cage. Erwin stepped forward to help him, kneeling to peel back the cloth tape holding the bandage in place. He scowled. 

“He received that wound from one of the first vectors,” Grisha told them. “Over sixteen hours ago. As you can see it's already entered the first stages of healing.”

“Hanji?”

The doctor swooped around the table, all but shoving the bone saw into Dita Ness’s hands as they went. They laced their bloody fingers behind them, leaning in close. “Hmm … This is a human bite and it's healing. That’s all I can determine simply by looking.”

“It was direct transmission,” Grisha insisted. “There’s little reason for me to lie. You would take him with you anyway.” He nodded to Farlan’s children like he thought he knew something about that.  _ Not necessarily,  _ Levi thought, his eyes sliding sideways to the commander standing beside him. The children had come with Levi. Erwin would have taken them with him once--striving, as was his nature, to save what he could. He’d always been the type to collect broken pieces, thinking it his duty to put them back together if he had the power to do so. That had been years ago, before he’d become so surgically practical. If he was that same person now, Levi couldn’t say. 

The situation outside was changing. The controlled  _ pop, pop, pop  _ of muffled gunfire had lost its form, its pace quickening as the men outside fell back. Grisha lost Erwin’s attention, then. 

“Someone report.”

It was a long, tense moment before anyone got back to him. “We have another wave of vectors from the left hall. It’s too many to put down. They’ll be all over us in a second.”

“Retreat to the platform,” Erwin ordered. “We’ll blow the glass when the hall is clear and we’ll flank them.”

They could hear the order making its rounds--the shout rising in the hall. Soldiers came into view, walking backwards and firing on vectors that still weren’t visible from the lab as others trooped past. Some glanced in at them. Most didn’t. But there was some sort of holdup from the opposite direction as well. The soldiers were stopping, raising weapons, and it was clear what had happened before the news of it came. “We have vectors coming from the station. They must have followed the train from the last platform.” 

Erwin turned on Grisha. “If this virus is yours, you must be someone noteworthy. Do you have an override key?”

“For the door? No, I don’t. Only the heads of each department carried them.” 

“Search him,” Erwin ordered. Into the radio, he instructed. “If you can’t shoot your way through them try to work your way back to the door. We’re searching Jaeger for an override key.” 

“Your soldiers are dead,” Grisha said, but he did not struggle as Mike dragged him to his feet and Nanaba kneeled in front of him, starting at his ankles and moving quickly up his body. “You can crevice-search me if you like. That door isn’t opening.” 

“Shut the fuck up,” Nanaba snapped, thrusting her hands into his pockets. She stopped to look at the ID badge she found in one of them, casting it to the tile in disgust when it turned out to be standard issue. 

“Hanji,” Erwin said suddenly, stepping around the group by the window to get the preservative fluid that Grisha had dropped when Nanaba went for his throat. “Get what you need quickly. We may have to move fast in the next few minutes.” He ignored their initial instructions not to approach the table, uncapping the bottle as he went. Nile held the jar out for him to pour while Hanji prepared the bone saw, their hands steady despite the increasing futility of the situation outside, only feet away. They waited for Erwin to step out of range before the saw came back on. 

Auruo and Eld were standing again, still pressed to the cabinets as instructed, but staring in horror now at the scene that was unfolding just outside. Petra sat, her arms around Gunther, whose eyes were wide with shock. Standing uselessly in the center of the room, Levi looked down at the boy in his arms, at the older children huddled at the back of the lab, and moved. 

“You heard all of that about Eren?” Levi asked them. Their eyes moved to him. Nods. “Then you know how important it is that we all keep him safe.” 

Eld held out his arms, understanding. Levi passed the child over with little more protest from Eren than an unhappy moan and a little restless shifting. Eld held him like he knew what to do with children. Perhaps he’d had younger siblings before all this. He bent his head close to Eren’s ear and murmured something that had him stilling again. 

“What are you going to do?” Auruo asked. 

“Erwin is going to try and open the door so we can save some of the men outside. Vectors may try to get in, so we need as many guns on them as we have.” 

“Me, too,” he said, stepping forward. “I can shoot.” 

Levi hesitated, but he’d wanted to give them something to do other than stare at the carnage that was about to happen outside. He nodded minutely. “Stay beside me if the door opens.” 

Auruo nodded. 

“Erwin, both of us can shoot.”

The commander’s eyes fell briefly to Auruo, but he reached for his sidearm with little hesitation. “Ness, come over here for a moment.” 

The soldier barely seemed relieved to leave the table where Hanji was working at sawing the crown of the vector’s skull open. His face was grim and set as he reported quickly to Erwin. 

“I’m going to borrow your sidearm,” the commander warned him, brushing the blood-spattered labcoat aside so he could get to the other man’s belt. Dita held his gloved hands away from Erwin and complied without protest, even when he passed the weapon over to Auruo. “How badly does Hanji need you?”

“You can take him,” Hanji called.

“Get your rifle and be ready in case we’re breached.” 

Dita nodded and moved to strip the gloves from his hands, barely pausing to marvel at the way Auruo’s palm fell over the top of his new weapon’s slide, ready to chamber the next round as his thumb reached to flip the safety off. Nanaba’s cry of frustration, though, informed them that they hadn’t found an override key. 

The shouts outside had turned to screams as vectors poured down the hall from both ends, leaping nimbly through the bodies of their fallen and flinging themselves at the men that shot uselessly into their ranks. Some fell, but more came to fill the empty spaces they left, moving as quickly and dexterously as a colony of ants. These were not old vectors. They were all new, freshly infected and strong, furious but still discriminant. These would not destroy themselves conveniently so they could pass. They would kill or infect any living body they could reach and then they would wait. 

“Can we blow the window from in here?” Nanaba asked, her eyes measuring the dimensions of the lab and looking for someplace they could retreat from the glass shrapnel that would result from a blast like that, but it was already clear to most of them that it was too late. By the time they set the charges the men outside would be dead or infected and then the vectors would pour into the lab through the opening and there would be nowhere left for any of them to go. Levi saw the moment she realized it and it was terrible. 

“Commander, any time you want to find that key, Sir!” someone called over the radio, and they all went still. 

After a moment, Erwin’s hand rose. “They’re still looking. Don’t give up.” To the others, he said, “Don’t tell them we don’t have it. They’ll stop fighting.” 

Nanaba turned a helpless look on Mike, but Grisha was between them and her eyes fell on him instead. Levi could see in her face what she was going to do and he could have said something, called out, but he didn’t have it in him. It wasn’t as bad as he thought, in any case. He expected the darkening in her eyes to mean that Mike would be cleaning Grisha’s brain from his shoes, but all she did was reach up and grab the man roughly by the hair, swinging him around and forcing his face ruthlessly to the glass. One of the vectors looked up from the soldier it had in its grip, something long and stringy in its teeth snapping away from the soldier’s neck as he fell. It pressed its face to the other side of the window, its fingers pressing experimentally at the glass, then something drew its attention and it lurched back, its interest focused on more attainable targets. 

“You watch every last second of this,” the woman snarled. “Keep your eyes open, you sorry sack of  _ shit.” _

No one moved to stop her that time. 

Erwin didn’t look away from it either. He watched it all the way to the end, until the last gun gave a final, feeble  _ pop  _ and everything went silent and the vectors were left to mill around outside, their numbers thinned but not significantly weakened. It was nothing the last few of them could take on. Blowing the glass would have killed them all and yet, not blowing the glass looked like it had killed their commander. 

“Hanji,” the man rasped. “Status.” 

“Almost finished.” 

“We’re the only ones left for them to focus on. Hurry.” 

When Levi slid his fingers around the back of Erwin’s elbow, the man allowed it. He did not pull away, but Levi wasn’t sure if that was because he didn’t protest the touch or because he didn’t much feel it. He was coming back together right before Levi’s eyes, filing away the things he’d just seen exactly the same way Levi had filed Isabel and Farlan away. Later, it would all come out again, but Erwin was a soldier and with a soldier’s discipline he carried on. 

Just as the commander predicted, vectors were gathering at the glass in restless rows, straining to get around their neighbors to look in at them, to press hands and faces to the glass like they were testing its integrity. Hanji was just about the only one in the room who was able to ignore it, focusing solely on the task at hand. 

“Depending on how we place the charges, we could lethally wound a lot of them,” Erwin thought aloud. “But we would have to take the whole row of glass and that wouldn’t leave any cover for us but the supply closets. We’d have a hard time getting out fast enough to form ranks.” 

“You won’t need to,” Grisha spoke up from across the lab. Nanaba had released him, or Mike had pulled her away. Levi had been too busy watching Erwin to know which. The doctor would have a nice line of bruising along his cheek where Nanaba had introduced his face to the window, but he didn’t seem interested in the pain. Instead, he pointed over Erwin’s head to the ventilation duct. “Go right once you’re inside. It should run all the way out to the platform. It should be a straight shot.” 

Erwin considered the opening. It was just large enough to accommodate even Mike’s shoulders if he hunched them, but they would have to get rid of the grate. “Is there a latch on that?” he asked. 

Grisha shook his head. “They seal shut when quarantine protocols are initiated, so you’ll have to force the metal, but you can be fairly certain there won’t be anyone else in the duct system with you. I don’t know of much that can burn through metal outside of military equipment.”

“I have a thermite torch in my bag,” Erwin said. 

“I have one, too, if we need extra cartridges,” Mike volunteered. “Though it shouldn’t take more than two for this job.” 

“I’ll let you handle the breach. Even dragging one of those tables over, it’s going to be a bit of a reach.”

“Your munchkin could sit on my shoulders.” 

It took Levi a moment to realize they were talking about him. “You want me to handle thermite?” 

“It’s a torch,” Mike said, shrugging out of his bag to pull out the necessary parts. “You hold one end and push a button. It’s easier than shooting a gun. Here,” he tossed Levi a pair of welding gloves, only one of which he managed to catch, as the other hand still had Erwin’s sidearm in it. 

“Keep it,” the commander told him as he tried to hand it back. “You too, Auruo. Turn the safety back on.” 

Lacking any sort of holster to hold the thing with, Levi pushed the barrel into his back pocket and went to help Mike drag the extra lab table around the side of Hanji’s to the middle wall beneath the duct. The table wasn’t particularly heavy, but it was enormous and unweildy and would have been difficult to drag, not to mention, noisy. Considering all those fevered eyes looking in at them from outside, it was probably best not to be any more exciting than they strictly needed to be. Some of the vectors had the dead soldiers’ rifles and were slinging them against the glass. One even got the bright idea to turn the heavy butt of the weapon inwards and use it as a battering ram and the others were catching on, learning the most efficient way to deal out force. So far, the glass held, but it wasn’t built to withstand a constant assault from multiple points of impact and Levi wasn’t sure how long they had. He wasn’t any sort of engineer but he’d be willing to bet the answer was  _ not long.  _

“Well, come on, then,” he told Mike, hoisting himself onto the table and standing. The other man was busy with the thermite, twisting one of the cartridges into position and passing Levi a second. 

“You saw how I did that?” Mike asked, joining Levi on the table and moving to get his legs under him. “Twist until it snaps.” 

“Yeah, I got it.” Or he would figure it out. He swung the first leg over Mike’s enormous shoulder, waiting for the other man to catch his ankle before allowing the second to join it. Beneath him, Mike stood like he weighed nothing, getting him right up to the duct. The metal was dusty, but maybe that would help it burn a fraction of a degree hotter. No problem. 

“This won’t help you if you stick your face right in it,” Mike warned, passing one of the plastic face shields up to Levi. “It’ll just keep the sparks off you, so keep your head out of the way.” He edged to the side to make that possible. Levi would have to lean sideways and stretch his arm out fully to get to the duct, but no one would be showered in thermite residue from that angle, so it would have to work. “You have about two seconds of ignition per cartridge, but that metal is thin enough that it should punch right through. Try to get two edges with each one.” Mike passed the torch to Levi. “It’s ready to go.” 

“Are  _ you _ ready to go?” 

“More than ready. Get us the hell out of this room.” 

“Happily,” Levi answered grimly, pressing his finger into the button on the handle until the torch ignited. 

It was hot, even though the welding gloves. Levi squinted into the bright smoke and drew his hand down and over, hoping it was metal he was cutting through and not the wall. It was too bright to see where he was going and his eyes watered themselves closed, protesting the hot smoke. When the first cartridge was spent, he gripped it in one hand and twisted it out, surprised when it happened easily. “They make these things dangerously user friendly, don’t they?” 

“Yes, thank god. How did you do?” Mike waved the last billows of smoke aside, squinting up at the damage as he moved under the vent to give Levi access to the other side. 

“It isn’t my best work, but I think it went all the way through.” 

“It did,” Erwin called from below, standing at a better angle to see such a thing. Heartened by their success, Levi turned the other cartridge into place until he felt the snap Mike described. 

“The torch is ready when you are.” 

Mike shifted a little farther to the side and Levi felt him turn his head away. “Ready.” 

That time, it was up and over. As the second cartridge dimmed and went out, Levi almost feared that he hadn’t done it, that there was still some part of the grate stubbornly hanging on, but then the harsh ring of metal hitting metal announced to all of them that the vent had fallen inwards. None of them felt quite energetic enough to whoop, but there was a collective loosening of muscle as all of them felt for the first time in many long, difficult minutes that they might make it out of the laboratory alive. Hanji was the only one who did not relax, still bent carefully over their saw. 

“I’m dropping the grate,” Levi announced, mostly because he didn’t want the doctor jumping and accidentally sawing their hand off. They carried on even as the metal hit the floor, doggedly determined to have their virus-riddled human brain.

“Mike, start getting people into the duct. Ness goes up first. I want a shooter in the front, just in case. Nile, you follow him. I’ll finish assisting Hanji with the samples.” 

Nile nodded, stepping away from the table to comply. Dita was already pulling himself into the duct, pushing his bag and rifle ahead of him. “Watch the edge,” he called down to Nile. “It’s still hot. And sharp.” 

“Someone will need to put me down,” Grisha warned them, standing over by the window like he knew he wasn’t welcome near the others. “If you don’t, I’ll try to follow you, after.” He held up his arm like they could have possibly forgotten that the wound was there. “It won’t be long.” 

“No problem,” Nanaba said briskly, drawing on him. 

“Wait.” 

She turned to look at Erwin like he’d taken something precious from her. 

“Not with Eren here. Let him go up, first.” 

“You really think he’s going to remember?” she asked, but she lowered the weapon to comply. 

“Children next, then,” Erwin instructed, gently nestling the container of vertebra into the bottom of Hanji’s bag, where it was cushioned by an extra uniform shirt. “You’ll have to boost someone up with Eren so they can pass him in.” 

“I’ll go up with him,” Eld volunteered. He shrugged. “I already have him, anyway.” 

After Nile, Auruo went up, then he turned to take Eren from Eld. Petra climbed in behind him, and then Gunther. Hanji lowered the brain carefully into its jar as the children climbed up, whipping off their gloves to seal the top with a sigh. “I’d have liked fluid samples, but this will do. If Eren is what he says he is, it may not even be necessary, anymore.” 

“You have the most important parts,” Grisha assured them. “Fluids would be redundant at this point.” 

Hanji eyed him warily. “Is it true about Eren? Now that all the fuss is over, you can tell us the truth. He’s a child and he hasn’t done anything wrong. We’ll protect him despite what you’ve done.” 

“What I’ve done is irrelevant,” the doctor said callously. “Eren is exactly what I promised he is.” 

“You would do that?” Hanji asked. “Experiment on your own son?” 

“Wouldn’t you?” the man countered. “What I did was make him valuable and now you’re all going to protect him at any cost. Would you not do that for a son?” 

“Christ, do we need anything else from him?” Nanaba asked impatiently. 

Erwin gave himself a moment to consider what they knew and what they didn’t know. He would like to understand why, but they didn’t have time for luxurious questions like those. A spiderweb of hairline cracks had bloomed across the plate glass at the front of the lab, and they spread farther outwards with every strike. In moments, the whole thing would give and they still had several people to get into the ducts.

So Erwin said, “No.”  

“In that case, Doctor, I hope you go straight to hell.” And Nanaba pulled the trigger without blinking.

**Author's Note:**

> [I live here.](http://merkase.tumblr.com) Spoiler alert it's tumblr.
> 
> I woke up around 4am two nights (mornings?) ago from a detailed dream about basically this and at least 80% of the O2 timeline came from there. I don't know what my brain was doing that night, but good job, brain. O2 may not update weekly the way Wild-Type does because I'm still prioritizing that fic and this one will be worked around it, but it should be pretty frequent nonetheless. Thank you, everybody, ILU. <3


End file.
